Electric fuse or cut-out.



No. 801,467. PATENTED OUT. 10, 1905. B. S. LUTHER 61: L. B. BUCHANAN.

ELECTRIC FUSE OR GUT-OUT.

APPLICATION FILED MAB. 6, 1905.

l lllf llli ll lll UNITED sTATEs PATENT oEEIoE.

BENJAMIN S. LUTHER, OF BOSTON, AND LEONARD B. BUCHANAN, OF

'WOBURN, MASSACHUSETTS, ASSIGNORS TO CHASE-SHAWMUT COM- PANY, OF NEWBURYPORT, MASSACHUSETTS, A CORPORATION OF MAINE.

ELECTRIC FUSE OR CUT-OUT.-

Specification of Letters Patent.

Patented Oct. 10, 1905.

Application filed March 6, 1905. Serial No. 2&8379.

1'0 a/ZZ whom, it may concern.

Be it known that we, BENJAMIN S. LUTHER, of Boston, county of Suffolk, and LEONARD B. BUCHANAN, of Woburn, county of Middlescx,

State of Massachusetts, have invented an Improvement in Electric Fuses or Cut-Outs, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention relates to an improved indicating mechanism for inclosed electric fuses or cut-outs; and its object is to secure certainty of operation and safety from fire and simplicity of construction to a greater degree than has hitherto been possible in such fuses.

The invention consists in providing a separate compartment within the casing of the ordinary cylindrical inclosed fuse for the indicating mechanism having no opening except through the casing, so that no product of the melting or vaporizing of the main fuse-wire can communicate therewith or pass therethrough to the exterior of the casing and so that the pressure of the gases formed in the indicating-compartment will have no escape except by operating the indicating device, and also in means for forming gas in the indicatingcompartment on the blowing of the main fusewire and causing the same to operate indirectly on an indicating device by compressing the air under it and so expelling it from a hole in the casing, and also in means for cooling said gas and removing burning particles therefrom, so that any part thereof passing out of said indicating-compartment will not communicate fire to any inflammable material outside.

The invention also consists in other features of construction. fully explained hereinafter.

Figure 1 shows inside elevation an electric fuse or cut-out embodying this invention. Fig. 2 shows a longitudinal section of the electric fuse or cut-out shown in Fig. 1. Fig. 3 is an enlarged longitudinal sectional detail of the indicating device, the gas producing element, and the means for supporting the fusewire and gas-producing element. Fig. A is a transverse section of the parts shown in Fig. 3. Fig. 5 is a plan view of the flame-resisting screen removed. Fig. 6 is an end view of the flame-resisting screen shown in Fig. 5. Fig. 7 is an under side view of the parts shown in one of the end caps a.

Fig. 3. Fig. 8 is a plan view of the support for the fuse-wire and the gas-producing element in the indicating-compartinent. Fig. 9 is a vertical section of the parts shown in Fig. 8 and the imperforate plate which serves as a separating-wall between the main compartment and incheating-compartment. Fig. 10 is a transverse section of the fuse or cut-out having an indicating device embodying this invention, showing means for reinforcing the separating-wall between main and indicating compartments.

(0 represents the cylindrical tubular body of the shell or case,and a a the terminals thereon, here shown as metallic end pieces or caps.

6 is the main fuse-wire, which is contained in the shell or case and which is herein shown as a strip of fusible metal connected at its ends to the metallic terminals, thereby extending longitudinally through the shell or case; but one strip is herein shown for the sake of simply illustrating the invention, although as many strips may be employed as desired. In large fuses a number of strips will usually be employed.

The shell or case is filled with anhydrous plaster-of-paris or any other of the finelydivided or porous non-conducting refractory materials commonly used in filling inclosed fuses.

An additional fuse-wire 5, preferably of fine German-silver wire, also passes through the shell or case and is electrically connected at its ends to the terminals in any suitable manner, said wire shunting the main fusewire I), and being of high resistance will carry only a trivial part of the current until the main fuse-wire has melted.

As a means of securing the shunt fuse-wire Z) in place each end of the body a may be formed with a slit, as shown at U, and the end portions of the fuse-wire drawn into these slits until they become wedged therein and the free ends of the wire then soldered to the caps to secure the electrical connection; but other methods of electrical connection with the terminals will be obvious.

The shell or case is provided with a hole 0 of circular or other form, which is preferably located near one end thereof, and, as herein shown, said hole is made in the body a near The indicating de-' rial.

vice is located at this hole, and, as herein shown, it consists of a circular piece (Z of leather or other suitable material adapted to be placed in the hole, so as not to project beyond the exterior line of the case and to be retained therein by friction; yet so far as our invention is concerned the indicating device may be otherwise constructed. The indicatingpiece 01 is designed to be ejected from the hole solely by pressure produced in the indicating-compartment.

The fuse-wire b, which passes along the inside of the shell or case, crosses the hole 0, and at said hole the indicating-compartment is formed through which said fusewire 6 passes, as will be described. it t represent two plates or pieces (see Figs. 8 and 9) of material, such as cloth, placed one upon the other, with the fuse-wire 6 between them, said plates or pieces being attached together and made large enough to more than cover the hole at the inside of the shell or case. The plates or pieces t tlare each formed with a circular hole 25 through them, and the fusewire Z) crosses this hole, and said plates or pieces are so located with respect to the hole 0 in the shell or case that the hole t therethrough lies opposite said hole 0. These plates or pieces support the fuse-wire b in the indicating-compartment.

The gas-producing element employed consists of a plate or disk 6 (see Fig. 9) of any suitable material, having upon one side of it a small quantity of gas-producing material 0', as gunpowder, for instance, which is laid thereon and held in place by adhesive mate- The gas-producing element is placed against the under side of the plates or pieces t t, being preferably adhesively attached thereto, and so located with respect thereto that the gas-producing material 0' lies opposite or enters the hole in said fuse-wire sup port 2? t.

In order to prevent the gases produced in the main compartment of the shell or case or other results of the fusion of the main fusewire 6 from passing through the fuse-wire support t 2? and manifesting themselves at the hole 0, either by the expulsion of flame therefrom or otherwise, a piece .11, of fiber (preferably of the same material as the body a) is disposed next the gas-producing element, so as to inclose the actuating means for the indicator in a separate compartment. The piece serves as an imperforate wall, separating the indicating-compartment from the main compartment. The imperforate wall a of the indicating-compartment also serves to cause the pressure caused by the explosion of the gas-producing element to seek relief by the expulsion of the indicator rather than by dissipation in the porous filling of the fuse. To further separate the compartments and to better hold the parts assembled, a comparatively large piece of cloth f, preferably having its meshes filled with glue or sizing, is employed, which covers the imperforate wall or plate a and is adhesively or otherwise attached to the wall of the case.

In case the cloth f and wall or plate n should not be strong enough to resist the shock of the explosion of the fuse-wire or to resist the pressure produced in either compartment of the fuse, a reinforcing-wall will be provided, as represented in Fig. 10, wherein a split tubular body m is fitted into the case which bears against the wall which separates the main and indicating comparti'nents. As a further precaution it is desirable (particularly in large fuses) to place vents at the end of the fuse in the caps a a to relieve the pressure from the main wire in case its fusion is accompanied by too serious a shock.

It will be observed that the fuse-wire passes through the indicatingcompartment thus formed, and the gasproducing element is contained therein; but so far as forming or producing said indicatingcompartment is concerned we do not limit our invention to the particular means herein shown for covering the hole at the inside of the shell or case, as it is obvious that said compartment may be otherwise formed and yet contain the gas producing material and have the fuse-wire pass through it, the idea being to produce a closed compartment of small dimensions back of the indicator through which the fusewire passes and which shall contain the gasproducing material.

To prevent the passage of any flame through the hole 0, containing the indicator (Z, when the fuse-wire b melts, a flame-resisting screen .9 is employed, of fine mesh, which is made large enough to at least cover the hole. This screen is placed next to the shell or case, between it and the plates or pieces 2? 2i, and the opposite edges of said screen are turned over the edges of the plates 23 t, which results in holding the parts assembled. This screen is formed with a central projection s of a diameter approximately as large as the hole 0 in the shell or case and said projection extends into said hole, as shown. The projection assists in holding the screen in place and also serves as a stop for the indicator (Z and also provides a cavity to insure the production of a small air-compartment back of the indicator.

It is obvious that on the fusion of the main fuse the shunt-wire b will melt and explode the gas-producing element. The gas thus produced will compress the air in the indicating-compartment back of the indicator and the pressure will be relieved by the ejection of the indicator; but the screen will cool any gases incident to the explosion which may pass through the screen after the indicator has been ejected and will remove any burning particles therefrom, so that they will not set fire to substances surrounding the fuse.

Having thus described our invention, what we claim as new, and desire to secure by Letters Patent, is-

1. In an electric fuse or cut-out, a shell or case having a main compartment and an indieating-compartment separated by an imperforate Wall, a fuse-wire in the main compartment, a fuse-Wire in the indieatingcompartment, an indicating device in the indicatingcompartment, and a gas-prod ucing element in said indicating-compartment, disposed adjacent the fuse-Wire, for increasing the pressure therein to operate the indicating device, substantially as described.

2. In an electric fuse or cut-out, a shell or case having a hole, an indicating device at said hole, an imperforate wall in said shell or case at said hole, which provides an indicating-compartment including said indicating device, a fuse-Wire contained in the shell or case, a fuse-Wire extending through said indicating-compartment, and means operated by the blowing of the fuse-wire in the indieating-compartment for operating the indieating device Without shattering the imperforate wall, substantially as described.

3. In an electric fuse or cut-out, a shell or case having. a hole, an indicating device at said hole, an imperforate wall in said shell or case at said hole, which provides an indicating compartment substantially separating said hole from the main fuse-wire, a main, a fuse-Wire contained in the shell or case, an additional fuse-wire extending through said indicating-compartment, and gas producing material contained in said indicating-compartment, substantially as described.

4;. In an electric fuse or cut-out, a shell or case having a hole, an indicating device at said hole, an imperforate wall in said shell or case at said hole, which provides an indicating compartment substantially separating said hole from the main fuse-wire, a main fuse-wire contained in the shell or case, an additional fuse-Wire extending through said indicating-compartment, gas-producing material in said indicating-compartment and a flame-resisting screen at said hole, between the gas-producing material and the indicating device, substantially as described.

5. In an electric fuse or cut-out, a tubular shell or case having terminals at its ends and having a hole near one of said terminals, an indicating device at said hole, an imperforate plate attached to the interior of said shell or case, which crosses the hole and provides a small compartment including the indicating device, a fuse-wire in the shell or case, electricall y connected to the terminals and a fusewire in the compartment back of the indicating device, substantially as described.

6. In an electric fuse or cut-out, a tubular shell or case having terminals at its ends and having a hole near one of said terminals, an indicating device at said hole, an imperforate plate attached to the interior of said shell or case, which crosses the hole and provides a small compartment including the indicating device, a fuse-wire in the shell or case, electrically connected to the terminals, a fuse-wire in the compartment back of the indicating device, and a gas-producing element in said compartment bacl: of the indicating device, adjacent the fuse-wire, substantially as described.

7. In an electric fuse or cutout, a case of insulating material having a hole, and metal terminals, a main fuse-wire in said ease electrically connected with said terminals, a filling of finely-divided non-conducting refractory material surrounding said main fuse-wire, an additional fuse-wire of low electrical capacity extending through said case near the hole therein and also connected electrically to said terminals, a partition-wall insaid case, about said hole, forming a small compartment through which said additional wire extends, substantially closed to communication with the main compartment of the case, a gas-producing element in said compartment in contact with said additional fuse-wire and operated by the fusion thereof, a flame-resisting screen between said gas-producing element and said hole, and an indicator in said hole adapted to be expelled therefrom by the pressure caused by the production of gas by said gas-producing element, substantially as described.

8. In an electric fuse or cut-out, a shell or case having a hole, an indicating device at said hole, a fuse-wire contained in said shell or case adjacent said hole, a support therefor attached to the shell or case having a hole through it, across which the fuse-wire extends, a gasproducing element placed against said sup port, the gas-producing material of said element being disposed opposite the hole in said support, substantially as described.

9. In an electric fuse or cut-out, a shell or case having a hole, an indicating device at said hole, a fuse-wire contained in said shell or case adjacent said hole, a support for said fusewire consisting of a pair of plates between which the fuse-wire extends, each of said plates having a hole through it, and a gas producing element located adjacent to said support, substantially as described.

10. In an electric fuse or cut-out, a shell or case having a hole, an indicating device at said hole, a fuse-wire contained in said shell or case adjacent said hole, a support for holding the fuse-wire at said hole, consisting of a pair of plates adapted to receive the fusewire between them, each of said plates having a hole through it, a gas-producing element located adjacent to said support, and an imperforate wall separating said parts from the main compartment of the shell or case, substantially as described.

11. In an electric fuse or cut-out, a shell or case having a hole, an indicating device at said hole, a fuse-wire contained in said shell or case adjacent said hole, a support for holding the fuse-wire at said hole, consisting of a pair of plates adapted to receive between them the fuse-Wire, substantially as described.

12. In an electric fuse 0r cut-out, a shell or case having a h0le,a fuse-Wire contained in said shell or case adjacent said hole, an indicating device at said hole, and a flame-resisting screen crossing said hole, substantially as described.

13. In an electric fuse or cut-out, a shell or case having a hole,a fuse-Wire contained in said shell or case adjacent said hole, an indicating device at said hole, a gas-producing element adjacent said fuse-wire, and a flame-resisting screen interposed between the fuse-wire and indicating device, which crosses said hole, substantially as described.

14. In an electric fuse or cut-out, a shell or case havinga hole,a fuse-wire contained in said shell or case adjacent said hole, an indicating device at said hole, a flame-resisting screen crossing said hole, which is interposed between the fuse-Wire and indicating device. and is formed With a cavity to provide a chamber adjacent the fuse-wire, substantially as described.

15. In an electric fuse or cut-out, a shell or case having a hole, a fuse-wire in said shell or case adjacent said hole, an indicating device at said hole, a flame-resisting screen crossing said hole, which is interposed between the fusewire and indicating device and is formed with a projection which enters said hole, substantially as described.

16. In an electric fuse or cut-out, a shell or case having a main compartment and an indieating-compartment separated by an imporforate wall, the indicating-compartment having an exit through the wall of the shell or case. a fuse-Wire in the main compartment, a fuse-wire in the indicating-compartment, an indicating device in the indicating-compartment which closes its exit and is adapted to be ejected therefrom, and means contained in said indicating-compartment adapted to be operated by the blowing of the fuse-wire therein for ejecting the indicating device, substantially as described.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

BENJAMIN S. LUTHER. LEONARD B. BUCHANAN. l/Vitnesses:

B. J. NOYES, H. B. DAVIS. 

